Synthesis of layered double hydroxides/graphene oxide nanocomposite as a novel high-temperature CO2 adsorbent

In this contribution, a novel high-temperature CO2 adsorbent consisting of Mg-Al layered double hydroxide(LDH) and graphene oxide(GO)nanosheets was prepared and evaluated. The nanocomposite-type adsorbent was synthesized based on the electrostatically driven self-assembly between positively charged Mg-Al LDH single sheet and negatively charged GO monolayer. The characteristics of this novel adsorbent were investigated using XRD, FE-SEM, HRTEM, FT-IR, BET and TGA. The results showed that both the CO2 adsorption capacity and the multicycle stability of LDH were increased with the addition of GO owing to the enhanced particle dispersion and stabilization. In particular, the absolute CO2 capture capacity of LDH was increased by more than twice by adding 6.54 wt% GO as support. GO appeared to be especially effective for supporting LDH sheets. Moreover, the CO2 capture capacity of the adsorbent could be further increased by doping with 15 wt%K2CO3. This work demonstrated a new approach for the preparation of LDH-based hybrid-type adsorbents for CO2 capture.     

Fundamentals in CO_2 capture of Na_2CO_3 under a moist condition

Capacity and kinetics of CO_2 capture of Na_2CO_3 were studied to determine the mechanism for CO_2 sequestration under ambient conditions. Bicarbonate formation of Na_2CO_3 was examined by a thermogravimetric analysis(TGA) under various CO_2 and water vapor concentrations and the accompanying structural changes of Na_2CO_3 were demonstrated by X-ray diffraction(XRD). Morphological variations were observed during the reaction of CO_2 capture through scanning electron microscope(SEM). Structural changes and morphological variations, which occurred during the course of the reaction, were then connected to the kinetic and exothermic properties of the CO_2 capture process from the XRD and SEM measurements. The results showed that the bicarbonate formation of Na_2CO_3 has two different pathways.For higher CO_2 and H_2O concentrations, the bicarbonate formation proceeded effectively. However, for lower CO_2 and H_2O concentrations, the reactions were more complicated. The formation of Na_2CO_3·H_2O from Na_2CO_3 as the first step, followed by the subsequent formation of Na_5H_3(CO_3)_4, and then the bicarbonate formation proceeds. To understand such fundamental properties in CO_2 capture of Na_2CO_3 is very important for utilization of Na_2CO_3 as a sorbent for CO_2 capture.     

Review on electrochemical carbon dioxide capture and transformation with bipolar membranes

Anthropogenic carbon dioxide(CO₂ ) emission from the combustion of fossil fuels aggravates the global greenhouse effect. The implementation of CO₂ capture and transformation technologies have recently received great attention for providing a pathway in dealing with global climate change. Among these technologies, electrochemical CO₂ capture technology has attracted wide attention because of its environmental friendliness and flexible operating processes. Bipolar ...     

Self-assembly of DNA Nanostructures via Bioinspired Metal Ion Coordination

Despite a growing interest in DNA nanomaterials,their simple synthesis remains a challenge.A simple and general strategy for constructing DNA-based nanomaterials by metal ion coordination is reported.The me-tal-DNA nanoparticles(NPs)could be synthesized with DNA molecules of diverse sequence and various metal ions of intrinsic property,resulting in multifunctional NPs with the combined advantages of both inorganic and DNA building blocks.It is demonstrated that the hybrid metal-DNA NPs could be engineered for magnetic resonance and luminescence imaging,encapsulation of multifarious nucleic acids with controlled ratio,and co-assembly with small drug molecules.Furthermore,because these metal-DNA NPs exhibited enhanced cellular uptake compared to free synthetic DNA,they hold potential for applications in diagnostics and therapeutics.     

Aversatile β-cyclodextrin functionalized silver nanoparticle monolayer for capture of methyl orange from complex wastewater

The toxic organic dye contaminants in wastewater are extremely harmful to the ecosystem.Surface enhanced Raman scattering(SERS) is a technique with high sensitivity and chemical specificity which fulfills the requirements for monitoring dye contaminants in wastewater.However,as one of the common dye contaminants,methyl orange(MO) has very weak affinity to metallic surfaces and is difficult to be detected by SERS at low concentrations.Therefore,a new type of SERS substrate with Ag nanoparticle monolayer functionalized by mono-6-deoxy-6-thio-β-cyclodextrin(β-CD-SH) was prepared to efficiently capture and detect MO in wastewater with a limit of detection of 5×10^-7 mol/L.The hydrophobic cavity of β-CD is responsible for the efficient trap and enrichment of MO on the Ag NPs surface,achieving a strong SERS signal of MO at low concentrations and at different pH values.This study provides new insight into designing a well-performed adsorbent for the capture and detection of organic contaminants.     

Structural transformations of carboxyl acids networks induced by concentration and oriented external electric field

The effects of concentration and an oriented external electric field on the transformations of hydrogenbonded structures of trimesic acid(TMA) and terephthalic acid(TPA) have been investigated at a liquidsolid interface by scanning tunneling microscopy(STM).The triangular periodic TMA framework can be transformed into a flower-like structure by changing the STM sample bias sign in situ.Networks of TMA and TPA are porous at a negative substrate bias,but typically change to relatively compact forms when the polarity of the applied bias is reversed.This change is reversible if the applied bias is reversed.The effects have potentials to locally control the capture and release of analytes in host-guest systems and the 2D morphology in multicomponent layers.     

Efficient CO2 capture on low-cost silica gel modified by polyethyleneimine

In this work,a series of polyethyleneimine(PEI) functionalized commercial silica gel were prepared by wet impregnation method and used as CO 2 sorbent.The as-prepared sorbents were characterized by N 2 adsorption,FT-IR and SEM techniques.CO 2 capture was tested in a fixed bed reactor using a simulated flue gas containing 15.1% CO 2 in a temperature range of 25-100 C.The effects of sorption temperature and amine content on CO 2 uptake of the adsorbents were investigated.The silica gel with a 30 wt% PEI loading manifested the largest CO 2 uptake of 93.4 mg CO 2 /g adsorbent(equal to 311.3 mg CO 2 /g PEI) among the tested sorbents under the conditions of 15.1%(v/v) CO 2 in N 2 at 75 C and atmospheric pressure.Moreover,it was rather low-cost.In addition,the PEI-impregnated silica gel exhibited stable adsorption-desorption behavior during 5 consecutive test cycles.These results suggest that the PEI-impregnated silica gel is a promising and cost-effective sorbent for CO 2 capture from flue gas and other stationary sources with low CO 2 concentration.     

Development of a competitive format sorbent assay for the determination of parathion in water using molecular imprinted polymer as specific sorbent carrier

<正>A rapid,simple,and reliable competitive molecular imprinted polymer sorbent assay(MIPSA) was developed and validated for measurement of parathion in water samples.This assay employed a molecular imprinted polymer(MIP) that was synthesized with non-covalent imprinting method as capture reagent and p-aminoparathion conjugate of horseradish peroxidase(para-HRP) as an enzyme label.The assay depended on a competitive binding reaction between the enzyme conjugate and analyte for the binding sites of the MIP.The optimized analysis conditions of 10 ng mL~(-1) para-HRP and 10 mg mL~(-1) polymer were found.The assay was acceptable to detect parathion in water samples under the optimized conditions,with a limit of detection of 50 ng mL~(-1).Mean analytical recoveries of added parathion in water samples ranged from 101.2%to 105%.The precision of the assay was satisfactory; relative standard deviation ranged from 4.3%to 6%.     

Fluorescent polymer-modified gold nanobipyramids for temperature sensing during photothermal therapy in living cells

The temperature monitoring of treated cancer cells is critical in photothermal therapy. Current methods of detecting intracellular temperatures have low accuracy and poor spatial resolution, which limits their application to photothermal therapy. Herein, a strategy for targeted recognition and selective capture of MCF-7 breast cancer cells based on fluorescent polymer poly(N-isopropylacrylamide-benzoxadiazole-2-vinyl-4,4-dimethyl azlactone, PNMV) and modified gold nanobipyramids(Au NBPs-PNMV) wa...     

Investigation of the role of Ca(OH)_2 in the catalytic Alkaline Thermal Treatment of cellulose to produce H_2 with integrated carbon capture

The Alkaline Thermal Treatment(ATT)of biomass is one of the few biomass conversion processes that has a potential for BECCS(bio-energy with carbon capture and storage).Combining in-situ carbon capture withcreates a carbon-neutral process that has the potential to be carbon-negative.This study has shown that the conversion of cellulose tosuppressedcan be achieved through the reforming of gaseous intermediates in a fixed bed of 10%Ni/ZrO_2.Reforming occurs at low temperatures≤773 K,which could allow for improved sustainability.     

First assessment of Li_2O–Bi_2O_3 ceramic oxides for high temperature carbon dioxide capture

The capacity to capture CO_2 was determined in several stoichiometric compositions in the Li_2O–Bi_2O_3 system. The compounds(Li_7BiO_6, Li_5BiO_5, Li_3BiO_4 and LiBiO_2 phases) were synthesized via solid-state reaction and characterized by X-ray diffraction, scanning electron microscopy and N2 adsorption techniques.The samples were heat-treated at temperatures from 40 to 750 °C under the CO_2 atmosphere to evaluate the carbonate formation, which is indicative of the capacity of CO_2 capture. Moreover, Li_7BiO_6 shows an excellent CO_2 capture capacity of 7.1 mmol/g, which is considerably higher than those of other previously reported ceramics. Li_7BiO_6 is able to react with CO_2 from 240 °C to approximately 660 °C showing a high kinetic reaction even at CO_2 partial pressure values as low as 0.05.     

Fluorescent polymer-modified gold nanobipyramids for temperature sensing during photothermal therapy in living cells

The temperature monitoring of treated cancer cells is critical in photothermal therapy. Current methods of detecting intracellular temperatures have low accuracy and poor spatial resolution, which limits their application to photothermal therapy. Herein, a strategy for targeted recognition and selective capture of MCF-7 breast cancer cells based on fluorescent polymer poly(N-isopropylacrylamide-benzoxadiazole-2-vinyl-4,4-dimethyl azlactone, PNMV) and modified gold nanobipyramids(Au NBPs-PNMV) wa...     

Endonuclease-rolling circle amplification-based method for sensitive analysis of DNA-binding protein

A sensitive approach for the qualitative detection of DNA-binding protein on the microarray was developed.DNA complexes in which a partial duplex region is formed from a biotin-primer and a circle single strand DNA(ssDNA) were spotted on a microarray. The endonuclease recognition site(ERS) and the DNA-binding sites(DBS) were arranged side by side within the duplex region. The working principle of the detection system is described as follows:when the DNA-binding protein capture the DBS,the endonuclease co...     

Researches on Formation of Haloacetic Acids in Chlorination of Drinking Water by a Novel Technique

Haloacetic acids (HAAs) are formed during the chlorination of drinking water, which are harmful to peo-ple′s health due to their carcinogenic and mutagenic effects. In the present study, a detection method combin-ing methyl tert-butyl ether (MtBE) extraction with acid catalysis and gas chromatography coupled with anelectron capture detector (GC/ECD) was developed for determining HAAs. The detection limit of this method(MDL) and relative standard deviation (RSD) were below 0. 37μg/L and 6.2%, respectively. The laboratorychlorination experiments were conducted with the purpose of investigating the influences of reaction time,temperature, UV254, bromide and ammonia-nitrogen on the formation of HAAs. The results show that theformation amount of HAAs increases with increasing reaction time and temperature, respectively;and thereexists a linear relationship between the formation of HAAs and UV254. The formation amount of HAAs de-creases first and then increases as the bromide ion concentration increases, and adding NH4^ is a possible wayto control the formation of HAAs.     

Adsorption of helical and saddle-shaped oligothiophenes on solid surface

The arrangement of oligothiophenes is essential for understanding the relationship between structure and properties particularly in the organic electronic field. The self-assembly behaviors of helical(TMS)2-[7]helicene(T1), naphthalene-cored double(TMS)2-[7]helicene(T2), and saddle-shaped cyclooctatetrathiophene(T3), its derivative α,α,α,α-tetraphenyl-cyclooctatetrathiophene(T4) on solid surface are firstly investigated by using a combination of scanning tunneling microscopy(STM) and density functional theory(DFT) calculation. 1,3,5-Tris(10-carboxydecyloxy)-benzene(TCDB) is selected to build flexible host networks to immobilize these oligothiophenes in order to capture their molecular adsorption images successfully. The observed monodisperse or polydisperse filling and long-range alignment of oligothiophenes are described based on the non-covalent interactions and commensurate structure between olihothiophene and cavity. We speculate that those molecularly defined alignments could lead to significantly understanding the application of such ordered monolayer in organic electronic devices.     

SYNTHESES AND ANTIMICROBIAL ACTIVITY OF NOVEL POLYURETHANE IONOMERS

This study is concerned with the removal of Staph aureus from water by polyurethaneionomers. All the samples are quaternary ammonium salts which possess a positive chargeon the surface. The ratio of the soft segment to diisocyanate and chain extender is 1:2:1and the ionization degree is 100%. The ionomers strongly capture microbial cells on theirsurfaces in a living state and the hydrophilicity of polymer matrix used in the studyenhanced the affinity of the polymer for bacterial cells. The adhesion of the microorganismto polymer was due mainly to electrostatic interaction between them. The calculation ofthe viable cell count showed that D value for Staph.aureus is not proportional to the nitro-gen concentration. The microorganism capture ability of pyridinium-containing polymer isgreater than that of piperazine based samples.     

Ordered mesoporous Ba CO3/C-catalyzed synthesis of glycerol carbonate from glycerol and dimethyl carbonate

Ordered mesoporous Ba CO3/C composites were synthesized by a multi-component co-assembly method combined with a carbonization process using phenolic resol as carbon source, barium nitrate as barium precursor, and triblock copolymer Pluronic F127 as template. The synthesized materials were characterized by X-ray diffraction, transmission electron microscopy, N2 physical adsorption, thermogravimetric analysis, and temperature-programmed desorption of CO2. When Ba CO3 contents were increased from 9.1 wt% to 44.7 wt%, pore size increased from 3.1 to 4.3 nm and the BET(Brunauer-Emmett-Teller) surface area initially increased to a maximum value of 390 m2 g-1(at a Ba CO3 content of 18.5 wt%) before subsequently decreasing. Ba CO3 was well dispersed in the amorphous carbon framework, and no phase separation was observed. The mesoporous BaCO3/C composites exhibited high catalytic activities toward the transesterification of glycerol and dimethyl carbonate into glycerol carbonate. A glycerol conversion of 97.8% and a glycerol carbonate selectivity of 98.5% were obtained under the optimized reaction conditions.     

Facile synthesis of mesoporous WO3@graphene aerogel nanocomposites for low-temperature acetone sensing

Nanocomposites constructed by combining mesoporous metal oxides and graphene have received tremendous attention in wide fields of catalysis,energy storage and conversion,gas sensing and so on.Herein,we present a facile interface-induced co-assembly process to synthesize the mesoporous W03@graphene aerogel nanocomposites(denoted as mW03@GA),in which graphene aerogel(GA) was used as a macroporous substrate,mesoporous W03 was uniformly coated on both sides of graphene sheets through a solvent evaporation-induced self-assembly(EISA) strategy using diblock copolymer poly(ethylene oxide)-b-polystyrene(PEO-b-PS) as a template.The resultant mW03@GA nanocomposites possess well-interconnected macroporous graphene networks covered by mesoporous W03 layer with a uniform pore size of 19 nm,high surface area of 167 m~2/g and large pore volume of 0.26 cm~3/g.The gas sensing performance of mW03@GA nanocomposites toward acetone and other gases was studied,showing a high selectivity and great response to acetone at low temperature of 150℃,which could be developed as a promising candidate as novel sensors for VOCs detection.     

Combination of extraction tip and MALDI-TOF-MS for efficient separation and analysis of cysteine-containing peptides

In our work,a new extraction tip with gold-modified polymer is developed.The simple,self-made and extremely economical tips were successfully applied to capture cysteine-containing peptides.The loading capacity of a tip(column bed:0.3 mm diameter,5 mm length)is 2–4μg peptides.We can make one tip in 30 s and each costs less than 0.1 cent.The use of these tips can achieve a stable analysis with less background interference,even for 10 ng target peptides.Compared with other separation techniques,our method can save much time and energy while providing a means to selectively capture cysteine-containing peptides from complex analyte due to the strong interaction.All results showed that our new extraction tips have minimal cost and perfect selectivity;thus they have great potential in sample pretreatment systems for proteomics.